Methods and apparatus for measuring the melt depth of a substrate during pulsed laser melting are provided. The apparatus can include a heat source, a substrate support with an opening formed therein, and an interferometer positioned to direct coherent radiation toward the toward the substrate support. The method can include positioning the substrate with a first surface in a thermal processing chamber, heating a portion of the first surface with a heat source, directing infrared spectrum radiation at a partially reflective mirror creating control radiation and interference radiation, directing the interference radiation to a melted surface and directing the control radiation to a control surface, and measuring the interference between the reflected radiation. The interference fringe pattern can be used to determine the precise melt depth during the melt process.
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2. The method of claim 1, wherein a plurality of reduced areas of the substrate are concurrently heated by directing focused radiation at each, and the method comprises concurrently determining the depth of the melt interface at each of the plurality of reduced areas.
3. The method of claim 1, wherein the control surface is a mirrored surface.
A method for controlling light reflection involves a control surface that is a mirrored surface. The mirrored surface is designed to reflect light in a controlled manner, allowing for precise adjustment of light direction and intensity. This method is particularly useful in optical systems where accurate light manipulation is required, such as in imaging, display, or lighting applications. The mirrored surface can be dynamically adjusted to alter the angle of reflection, enabling adaptive control over light paths. By using a mirrored surface, the method ensures high reflectivity and minimal light loss, improving the efficiency of the optical system. The adjustment of the mirrored surface can be achieved through mechanical, electrical, or other means, depending on the specific application. This approach enhances the versatility and performance of optical devices by providing a reliable and efficient way to manage light reflection. The method is particularly beneficial in applications where precise light control is critical, such as in advanced imaging systems or high-precision optical instruments.
4. The method of claim 1, wherein the substrate comprises silicon.
5. The method of claim 1, further comprising directing a coherent radiation towards a partially reflective mirror to generate the interference radiation and the control radiation.
6. The method of claim 1, wherein heating the reduced area of the first surface comprises directing a second coherent radiation there towards.
This invention relates to a method for processing a material surface using localized heating with coherent radiation. The method addresses the challenge of precisely controlling thermal treatment in specific regions of a surface to achieve desired material properties without affecting adjacent areas. The technique involves directing a first coherent radiation beam onto a reduced area of a first surface to heat it, followed by directing a second coherent radiation beam toward the same area. The second beam may have different characteristics, such as wavelength, intensity, or pulse duration, to further refine the heating process. The method may be used in applications like material hardening, annealing, or surface modification, where precise thermal control is critical. The use of coherent radiation allows for focused energy delivery, minimizing heat spread and ensuring localized treatment. The invention may also include additional steps, such as adjusting the beam parameters or scanning the radiation across the surface, to achieve uniform or patterned heating effects. The technique is particularly useful in industries requiring high-precision thermal processing, such as semiconductor manufacturing, metallurgy, or advanced materials engineering.
11. The method of claim 10, wherein the mirrored control surface is parallel to a direction of the coherent radiation directed from the coherent radiation source to the partially reflective mirror.
13. The method of claim 12, wherein the radiant interface detector is at least partially disposed beneath the backside of the substrate support.
A radiant interface detector is used in semiconductor processing to monitor and control the temperature of a substrate, such as a wafer, during manufacturing. The detector measures radiant energy emitted from the substrate to ensure precise temperature regulation, which is critical for maintaining uniformity and quality in processes like chemical vapor deposition (CVD) or physical vapor deposition (PVD). A challenge in such systems is accurately detecting radiant energy while avoiding interference from other heat sources, such as the substrate support or surrounding equipment. This invention improves upon prior designs by positioning the radiant interface detector at least partially beneath the backside of the substrate support. By placing the detector in this location, it can more effectively capture radiant energy emitted from the substrate while minimizing interference from the support structure. This configuration enhances measurement accuracy, ensuring better temperature control and process consistency. The detector may be integrated into the support or positioned in a way that allows it to sense radiation through openings or transparent regions in the support. The method also includes calibrating the detector to account for variations in substrate emissivity and environmental conditions, further improving reliability. This approach is particularly useful in high-precision semiconductor manufacturing where temperature uniformity is critical.
15. The method of claim 12, wherein the radiant interface detector further comprises a light selective barrier configured to selectively filter a wavelength corresponding to the laser radiation, and the reflected interference radiation and the reflected control radiation received at the radiation sensor are passed through the light selective barrier.
This invention relates to optical sensing systems, specifically for detecting and analyzing radiant interfaces using laser radiation. The problem addressed is the need for precise detection of reflected radiation while minimizing interference from unwanted wavelengths. The system includes a radiant interface detector that emits laser radiation toward a target interface and receives reflected radiation from the interface. The reflected radiation includes both the laser radiation and other interference radiation. To improve accuracy, the detector includes a light selective barrier that filters out unwanted wavelengths, allowing only the laser radiation and relevant reflected control radiation to pass through to a radiation sensor. This selective filtering ensures that the sensor receives only the desired signals, reducing noise and improving measurement precision. The system may also include additional components for generating and controlling the laser radiation, as well as processing the received signals to analyze the interface properties. The light selective barrier is designed to match the wavelength of the laser radiation, ensuring optimal filtering performance. This approach enhances the reliability of optical interface detection in applications such as material analysis, surface inspection, or industrial process monitoring.
16. The method of claim 12, wherein the radiant interface detector is an infrared interferometer.
18. The method of claim 12, wherein the substrate support further comprises a lens disposed between the substrate supporting side and the backside, and the lens is transparent to the interference radiation.
19. The method of claim 12, wherein the radiant interface detector is at least partially disposed in the substrate support between the substrate supporting side and the backside.
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February 15, 2019
November 1, 2022
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